Friction 5 : The resistance to movement created when two surfaces are in contact. When friction is present, heat is produced. (Sometimes referred to as "drag" in wireline operations). (WLOP)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}